An image forming apparatus of one type forms an image on a sheet (medium) and fixes the image on the sheet. Such an image forming apparatus may form the image with a non-decolorable material or a decolorable material. When the image is formed on the sheet with the decolorable material, the sheet can be reused after the image is erased.
In order to fix the decolorable material onto the sheet, the sheet needs to be heated, but not too much such that an image of the decolorable material is not erased.